Question

我有两个DataFrame：dfSide0和dfSide1，它们具有相同的列，但行数不同。 dfSide0有17096行，dfSide1有4961行。我想做的是获取dfSide0['distoperator']的值之间所有可能的减法中的最小值和dfSide1['distoperator']，但仅当条件dfSide0['camera_row'] == dfSide1['camera_row']为True时。

所以我执行以下操作：

temp = []
for i in dfSide0['distoperator']:
    if dfSide0['camera_row'] == dfSide1['camera_row']:
        c = min(abs(i - dfSide1['distoperator']))
        temp.append(c)

，我收到以下错误消息：

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-225-625fcefe40b7> in <module>()
      1 temp = []
      2 for i in dfSide0['distoperator']:
----> 3     if dfSide0['camera_row'] == dfSide1['camera_row']:
      4         c = min(abs(i - dfSide1['distoperator']))
      5         temp.append(c)

C:\ProgramData\Anaconda3\lib\site-packages\pandas\core\ops.py in wrapper(self, other, axis)
   1188 
   1189         elif isinstance(other, ABCSeries) and not self._indexed_same(other):
-> 1190             raise ValueError("Can only compare identically-labeled "
   1191                              "Series objects")
   1192 

ValueError: Can only compare identically-labeled Series objects

我该怎么办？

Answer 1

感谢您的快速响应。为了使事情更清楚： dfSide0和dfSide1都有两列：'distance'是浮点数，'camera_row'是具有值'a'，'b'，'c'，'d'，'e'和'f'的字符串 dfSide0具有17096行，dfSide1具有4961行。我需要减去两个数据帧之间的“距离”列中的所有值，并找到最小值，但前提是列“ camera_row”中的值相同。到目前为止，确切的代码如下：

temp = []
for i in dfSide0['distance']:
    c = min(abs(i - dfSide1['distance']))
    temp.append(c)

它可以工作，但是我还没有找到一种仅在

时才准确地为for循环执行此操作的方法

dfSide0['camera_row'] == dfSide1['camera_row']

Answer 2

如果我这样做：

temp = []
for i in dfSide0['distoperator']:
    if dfSide0['camera_row'] == dfSide1['camera_row']:
        c = min(abs(i - dfSide1['distoperator']))
        temp.append(c)

我得到以下信息：

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-222-625fcefe40b7> in <module>()
      1 temp = []
      2 for i in dfSide0['distoperator']:
----> 3     if dfSide0['camera_row'] == dfSide1['camera_row']:
      4         c = min(abs(i - dfSide1['distoperator']))
      5         temp.append(c)

C:\ProgramData\Anaconda3\lib\site-packages\pandas\core\ops.py in wrapper(self, other, axis)
   1188 
   1189         elif isinstance(other, ABCSeries) and not self._indexed_same(other):
-> 1190             raise ValueError("Can only compare identically-labeled "
   1191                              "Series objects")
   1192 

ValueError: Can only compare identically-labeled Series objects

没有if语句，它运行正常。

Answer 3

我想我找到了答案：

temp = []
k = -1
for i in dfSide0['distoperator']:
    k = k+1
    j = dfSide0.index[k]
    c = min(abs(i - dfSide1['distoperator'][dfSide1['camera_row'] == dfSide0['camera_row'][j]]))
    temp.append(c)

似乎可行！

Python中的条件循环

3 个答案: